The upper portion of a conventional package 30 is shown in FIG. 1, and the package includes a container 32 which has been filled with a fluent product (not visible). The container 32 has an upper opening 33 (FIGS. 2 and 5), and the top of the container 32 is covered or closed with a closure system or closure 36 (FIG. 1) which is mounted to the top of the container 32.
An optional “liner” seal member 38 (FIGS. 2 and 5) may be employed as part of the closure system. Typically, such an optional liner 38 is a membrane that includes at least one layer of thermoplastic material that can be heat-sealed to the top rim of the container 32 around the container opening 33. In FIG. 5, such a heat seal is schematically illustrated by the small triangles 40. If such an optional heat seal 38 is employed, the user of the package 30 (FIG. 1) must initially remove the closure 36 from the top of the container 32 and cut away or peal away the liner 38. Then the user can reinstall the closure 36 on the top of the container 32.
The illustrated form of the conventional closure 36 is mounted on the container 32 with a threaded engagement system. To this end, the container 32 typically includes a conventional thread 44 (FIGS. 2 and 5) for being threadingly engaged by the closure 36.
As shown in FIG. 4, the closure 36 includes a closure body or base 46 which has a peripheral skirt 48 depending downwardly from a deck 50. The center of the deck 50 merges into a upwardly projecting spout 52 which defines a dispensing orifice 54.
As can be seen in FIG. 5, the skirt 48 of the closure body 46 has an interior surface on which is formed a thread 58 for threadingly engaging the container thread 44. The closure body 46 could be mounted on the container 32 with other attachment systems, such as cooperating, releasable beads, or beads and grooves, so as to retain the closure body 46 and container 32 together in a sealing relationship. In other designs, the closure body 46, although separately manufactured from the container 32, could be subsequently permanently attached to the top of the container 32 by means of induction bonding, ultrasonic bonding, gluing, or the like, depending on the materials employed for the container and the closure body 46. In some applications, the closure body 46 may be molded as a unitary part, or extension, of the top of the container 32.
In the type of conventional closure 36 illustrated in FIGS. 2 and 5, the closure body 46 includes a pressure-actuatable, flexible, slit-type valve 60 which is held inside the spout 52 by means of an annular retainer ring 62 that is snap-fit into the spout 52. The valve 60 may be of the well-known type sold in the United States of America by Liquid Molding Systems, Inc., 2202 Ridgewood Dr., Midland, Mich. 48642, U.S.A.
The particular form of the valve 60 illustrated is molded as a unitary structure from material which is flexible, pliable, elastic, and resilient. This can include elastomers, such as a synthetic, thermosetting polymer, including silicone rubber, such as a silicone rubber sold by Dow Corning Corp. in the United States of America under the trade designation D.C. 99-595-HC. Another suitable silicone rubber material is sold in the United States of America under the designation Wacker 3003-40 by Wacker Silicone Company. Both of these materials have a hardness rating of 40 Shore A. The valve 60 could also be molded from other thermosetting materials or from other elastomeric materials, or from thermoplastic polymers or thermoplastic elastomers, including those based upon materials such as thermoplastic propylene, ethylene, urethane, and styrene, including their halogenated counterparts.
The design configuration of valve 60, and the operating characteristics thereof, are substantially similar to the configuration and operating characteristics of the valve designated by the reference number 3d in the U.S. Pat. No. 5,409,144. The description in that patent is incorporated herein by reference to the extent pertinent and to the extent not inconsistent herewith.
The valve 60 includes a recessed, central head which is flexible and which has an outwardly concave configuration (as viewed from the exterior of the valve 60 when the valve 60 is mounted in the spout 52). The head defines two, mutually perpendicular, intersecting slits of equal length extending through the head to define a normally self-sealing, closed orifice. The intersecting slits define four, generally sector-shaped, flaps or petals in the head. The flaps open outwardly from the intersection point of the slits in response to an increasing pressure differential of sufficient magnitude in the well-known manner described in the above-discussed U.S. Pat. No. 5,409,144.
The valve 60 has an interior side for facing generally into the spout 52 and an exterior side for facing generally outwardly from the spout 52. The interior side of the valve 60 is adapted to be contacted by the fluid product in the container 32, and the exterior side of the valve 60 is exposed to the ambient external atmosphere when the lid 70 is opened.
The valve 60 includes a thin skirt which extends axially and radially outwardly from the central, recessed valve head. The outer end portion of the skirt terminates in an enlarged, much thicker, peripheral flange which has a generally dovetail-shaped, transverse cross section and which is clamped by the retainer ring 62 to hold the valve 60 in the closure.
When the valve 60 is properly disposed in the spout 52, with the valve head in the closed condition, the valve head is recessed relative to the end of the spout 52 (FIG. 5). However, when the valve head is forced outwardly from its recessed position by a sufficiently large pressure differential across the valve, the valve 60 opens. More specifically, after the closure lid 70 (described in detail hereinafter) has been opened, and when the pressure on the interior side of the valve 60 exceeds the external ambient pressure by a predetermined amount, the valve head is forced outwardly from the recessed or retracted position to an extended, open position (not shown).
During the valve opening process, the valve head is initially displaced outwardly while still maintaining its generally concave, closed configuration. The initial outward displacement of the concave head is accommodated by the relatively, thin, flexible, skirt. The skirt moves from a recessed, rest position to a pressurized position wherein the skirt extends outwardly toward the open end of the spout 52. However, the valve 60 does not open (i.e., the slits do not open) until the valve head has moved substantially all the way to a fully extended position. Indeed, as the valve head moves outwardly, the valve head is subjected to radially inwardly directed compression forces which tend to further resist opening of the slits. Further, the valve head generally retains its outwardly concave configuration as it moves forward and even after the sleeve reaches the fully extended position. However, when the internal pressure becomes sufficiently great compared to the external pressure, then the slits in the extended valve head quickly open to dispense product.
As can be seen in FIG. 4, the closure 36 includes a lid 70 which, in a typical conventional arrangement, is hingedly connected to the closure body 46 with a snap-action type hinge 72. One form of such a snap-action type hinge 72 is described in the U.S. Pat. No. 6,321,923. Other types of hinges could be used. In some applications, the hinge could be omitted, and the lid need not be connected to the body at all.
As can be seen in FIG. 4, the lid includes a peripheral skirt 74 which depends from a top wall 76. Projecting form the inside of the top wall 76 is a sealing collar 78 which has a radially inwardly projecting, annular, sealing bead 80. The sealing bead 80 is an uninterrupted, convex structure which is adapted to engage the exterior of the spout 52, and the exterior of the spout 52 may be characterized as defining a first engaging surface 82 (FIG. 4). The lid sealing collar 78 may be characterized as an occlusion member for closing the spout 52 and having a second engaging surface of the lid sealing collar 78 for engaging the spout first engaging surface 82. In the illustrated embodiment, the second engaging surface is the annular sealing bead 80.
The lid 76 of the conventional closure 36 also includes a downwardly projecting member 86 (FIGS. 4 and 5). When the lid 76 is closed, the member 86 is spaced just above the central head of the valve 60. If the package is subjected to an over-pressure condition when the lid is closed (such as if the container 32 is impacted or squeezed after the liner 38 has been removed), then the upward, outward movement of the head of the valve 60 caused by such an internal over-pressure condition will be limited by engagement with the lid member 86 so as to prevent the valve 60 from opening inside the closed lid 70.
The above-described package 30 may be used for packaging a variety of products. However, it has been found that such a package 30 may be less desirable with some types of products that undergo certain kinds of processing. In particular, some products are packaged in a thermally hot condition. That is, prior to the closure 36 being installed on the open container 32, the open container 32 is filled by the product manufacturer with product that is thermally hot, and then subsequently, the liner 38 is installed on the container, and the closed closure 36 is mounted on the container 32. In other packaging processes for some types of food products, the product is not heated before it is introduced into the container; rather, after the closure is installed on the filled container, the entire package is moved to a pasteurizing station wherein the package is subjected to heat from an external source so as to raise the temperature of the product within the package to a sufficient magnitude and for a sufficient amount of time to effect pasteurization of the food product.
In any event, whether the product is hot-filled into a container that is subsequently closed with a closure, or cold-filled into a package that is subsequently closed with a closure and then heated as part of a pasteurization process, the heat can cause the interior atmosphere in the package to expand. Even where a sealing liner 38 and valve 60 are employed, as shown in FIG. 5, the internal atmosphere in the closure between the lid sealing collar 78 and the valve 60 can become heated so that the pressure increases and the internal atmosphere seeks to expand. It has been found that in a conventional, inexpensive, disposable, thermoplastic closure, a conventional sealing engagement between the closure lid and closure spout is not air-tight during such over-pressure conditions. Even an annular sealing bead, such as the sealing bead 80 (FIG. 5), does not provide air-tight sealing between the closure lid and closure body spout when there is a differential pressure across the sealing region as a result of a heat-induced, transient pressure increase in the closed region within the sealing collar 78. The pressure under the lid 70 on the exterior of the sealing collar 78 is substantially the same as the ambient atmospheric pressure around the exterior of the closure 36 owing to the significant gaps existing in the region of the hinge 72 at the hinge ends (designated in FIG. 3 by reference numbers 90). The heated, expanding internal atmosphere within the lid collar 78 leaks out between the lid annular seal 80 and spout exterior surface 82 (FIG. 5). The pressure around the lid collar 78 under the lid 70 remains substantially equal to the exterior ambient atmospheric pressure outside of the closure 36 owing to the significant openings at each edge 90 of the hinge 72 (FIG. 3).
The heated package (whether heated from initial hot filling of the product or subsequent pasteurization of a cold-filled product), typically is rapidly cooled in a subsequent step of the process. It is desirable to rapidly cool the package in order to facilitate subsequent processing operations, such as applying a label to each package and/or stacking the packages for further handling or shipping. If the package container 32 is made of a thermoplastic material, the heated container material loses much of its strength when it is hot, and the container wall can easily buckle or collapse during labeling processes or stacking processes. Thus, in typical high-speed, packaging process lines, the heated packages are quickly moved to and through a station which rapidly cools the packages prior to labeling and/or stacking.
The typical station used for cooling such packages incorporates a cooling tunnel wherein a cool water shower is sprayed onto the packages. The cool water shower reduces the temperature of the packages. However, as the temperature of a package decreases, the internal atmosphere within the closed spout cools, and the internal pressure begins to decrease. When a conventional package such as package 30 shown in FIG. 5 is cooled, there is a decrease in the temperature of the package interior, including in the temperature of the spout internal atmosphere in the region below the valve and in the region between the valve 60 and the closure lid sealing collar 78. This temperature decrease causes the pressure of the internal atmosphere within the closed spout 52 to decrease. This causes a partial vacuum (i.e., lower pressure) to be created inside of the closure lid sealing collar 78 relative to the external ambient atmosphere. However, the pressure differential between the higher pressure of the external ambient atmosphere and the lower pressure of the internal atmosphere draws some external ambient atmosphere past the sealing surfaces between the lid collar 78 and spout 52. Because the external ambient atmosphere in the cooling tunnel includes moisture in the form of water and water vapor, such water and/or water vapor can be drawn under the lid 70 and into the interior space inside the lid sealing collar 78. Further, some water may have been sprayed directly through the hinge open edges 90 and into the lid 70 and on the exterior of the spout 52 outside of the lid collar 78. Even when the package 30 has exited the cooling tunnel, water from the cool water shower can remain on and around the package closure exterior surfaces, especially at the closure hinge open edges 90 (FIG. 3). As the internal atmosphere within the lid collar 78 cools and contracts, the differential between the greater atmospheric pressure outside of the lid collar 78 and the lower pressure in the internal atmosphere inside of the lid collar 78 tends to draw in the moisture or water vapor past the annular seal bead 80 and into the internal volume within the lid sealing collar 78. Some of the moisture or water vapor being pulled in from the external ambient atmosphere may collect as water on the top surface of the deck 50 under the lid 70, and some is pulled all the way past the sealing collar 78. Some of the moisture or water vapor that is pulled past the sealing collar 78 could then eventually accumulate as liquid water in and around the spout opening 54, and also on the outwardly facing surface of the valve 60. If the package is of the type that does not have a valve 60, such infiltrating water and water vapor might reach the region directly above, or on, the liner 38. If no liner 38 is employed, then the water and water vapor could contact the product within the container 32.
The cooling spray water that has been pulled past the closure lid 70 (and that is deposited on the deck 50 and/or in other areas of the package inwardly of the lid sealing collar 78) presents an undesirable packaging condition. Cooling tunnel shower water is typically treated to inhibit growth of mold, bacteria, etc. However, the presence of water or water vapor on the deck 50 under the lid 70 and also inwardly of the lid spout seal region is undesirable from the standpoint of consumer perception when the consumer later opens the package by lifting the lid 70. Water under the closure lid in the dispensing orifice region may be regarded by the consumer as a problem with product quality or sanitary conditions. If a product manufacture had not properly treated the cooling spray water to inhibit the growth of mold, bacteria, etc., then the presence of water within the internal portion of the closure could lead to growth of mold, bacteria, etc.
The inventor of the present invention, and others, have investigated ways in which to minimize or eliminate the infiltration of cooling tunnel shower water onto the surface of the deck 50 under the lid 70 as well as into the interior of a closure beyond the closure lid seal. For a typical low-cost, disposable, dispensing closure molded from thermoplastic material, the inventors have been unable to design a readily manufactured closure that is easily openable by the consumer and that has an essentially 100% leak-tight seal to prevent cooling water ingress in response to a partial vacuum within the package during package cool-down.